/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.streaming.api.functions.sink.filesystem;

import org.apache.flink.annotation.Internal;
import org.apache.flink.core.fs.Path;

import java.io.IOException;

/**
 * An interface for factories that create the different {@link InProgressFileWriter writers}.
 */
@Internal
public interface BucketWriter<IN, BucketID> {

	/**
	 * Used to create a new {@link InProgressFileWriter}.
	 * @param bucketID the id of the bucket this writer is writing to.
	 * @param path the path this writer will write to.
	 * @param creationTime the creation time of the file.
	 * @return the new {@link InProgressFileWriter}
	 * @throws IOException Thrown if creating a writer fails.
	 */
	InProgressFileWriter<IN, BucketID> openNewInProgressFile(
			final BucketID bucketID,
			final Path path,
			final long creationTime) throws IOException;

	/**
	 * Used to resume a {@link InProgressFileWriter} from a {@link InProgressFileWriter.InProgressFileRecoverable}.
	 * @param bucketID the id of the bucket this writer is writing to.
	 * @param inProgressFileSnapshot the state of the part file.
	 * @param creationTime the creation time of the file.
	 * @return the resumed {@link InProgressFileWriter}
	 * @throws IOException Thrown if resuming a writer fails.
	 */
	InProgressFileWriter<IN, BucketID> resumeInProgressFileFrom(
			final BucketID bucketID,
			final InProgressFileWriter.InProgressFileRecoverable inProgressFileSnapshot,
			final long creationTime) throws IOException;

	/**
	 * @return the property of the {@link BucketWriter}
	 */
	WriterProperties getProperties();

	/**
	 * Recovers a pending file for finalizing and committing.
	 * @param pendingFileRecoverable The handle with the recovery information.
	 * @return A pending file
	 * @throws IOException Thrown if recovering a pending file fails.
	 */
	PendingFile recoverPendingFile(final InProgressFileWriter.PendingFileRecoverable pendingFileRecoverable) throws IOException;

	/**
	 * Frees up any resources that were previously occupied in order to be able to
	 * recover from a (potential) failure.
	 *
	 * <p><b>NOTE:</b> This operation should not throw an exception, but return false if the cleanup did not
	 * happen for any reason.
	 *
	 * @param inProgressFileRecoverable the {@link InProgressFileWriter.InProgressFileRecoverable} whose state we want to clean-up.
	 * @return {@code true} if the resources were successfully freed, {@code false} otherwise
	 * (e.g. the file to be deleted was not there for any reason - already deleted or never created).
	 * @throws IOException if an I/O error occurs
	 */
	boolean cleanupInProgressFileRecoverable(final InProgressFileWriter.InProgressFileRecoverable inProgressFileRecoverable) throws IOException;

	/**
	 * This represents the file that can not write any data to.
	 */
	interface PendingFile {
		/**
		 * Commits the pending file, making it visible. The file will contain the exact data
		 * as when the pending file was created.
		 *
		 * @throws IOException Thrown if committing fails.
		 */
		void commit() throws IOException;

		/**
		 * Commits the pending file, making it visible. The file will contain the exact data
		 * as when the pending file was created.
		 *
		 * <p>This method tolerates situations where the file was already committed and
		 * will not raise an exception in that case. This is important for idempotent
		 * commit retries as they need to happen after recovery.
		 *
		 * @throws IOException Thrown if committing fails.
		 */
		void commitAfterRecovery() throws IOException;
	}
}
